Medical treatments today often require that areas of organic tissue be cauterized or coagulated quickly, efficiently, and safely during the course of a surgical procedure. For example, surface tissue on a highly vascularized organ such as the human liver may be cauterized immediately following the making of a surgical incision in order to prevent excessive bleeding. Alternatively, retinal tissue in a human eye may be photocoagulated during opthalmic surgery to correct injury, or skin tissue on a human scalp may be coagulated during hair transplant surgery to prevent bleeding resulting from graft incisions. Many prior art devices have been developed to perform cauterization or coagulation as appropriate for such varied applications. Known devices range from simple direct-contact cauteries, employing a heated wire element to burn or sear relatively large areas of tissue, to more complex laser photocoagulators using highly coherent, monochromatic laser light to perform pin-point coagulation of delicate tissue.
One particular class of coagulator, of primary interest in the present application, includes devices employing noncoherent, broadband radiation, such as that produced by an incandescent light source, to achieve tissue coagulation. Such devices are extremely beneficial in that noncoherent radiation can be used effectively to coagulate tissue or blood in a wide variety of surgical applications. However, physical limitations associated with known devices in this class tend to limit their practical usefulness.
For example, because the intense heat generated by an incandescent light source can create discomfort, or even danger, for a user of such a device, typical prior art devices are configured to physically isolate a user's hand from the light source. See, for example, U.S. Pat. No. 4,233,493 and U.S. Pat. No. 4,884,568. Such devices tend to be bulky, and therefore awkward, from the perspective of a user attempting to perform a precise or lengthy surgical procedure. Other prior art devices rely on a combination of short-duration coagulation pulses and thick, heat sinking contact elements positioned between the light source and the tissue being coagulated to prevent over-heating. See, for example, U.S. Pat. No. 5,539,987. While such devices are more compact, the limitations imposed in order to prevent over-heating render these devices ineffective for many applications.
Additionally, each of the above cited prior art devices provides less than optimal efficiency in terms of transferring radiation from the light source to the tissue being coagulated. As a result, relatively high power levels must be used to achieve coagulation in a given context. This not only results in undue power consumption, but also adds to the over-heating problem just described. Thus, there is a need for a coagulating device providing improved radiation transfer characteristics and enabling a user to comfortably hold and manipulate the device during a surgical procedure.